The goal of this research is to evaluate a comprehensive test battery of new wide-bandwidth, i.e., wideband (WB), acoustical tests of auditory function in the differential diagnosis of middle ear, cochlear and neural pathologies in a population of Veterans. WB tests refer to ear canal tests using sound responses measured from 0.2 kHz to frequencies as high as 8 kHz, a bandwidth that is critical for speech perception. There will be tests in the battery for middle-ear assessment using power absorption, cochlear assessment using otoacoustic emissions (OAEs) and the acoustic stapedius reflex (ASR) using middle ear power absorption. Results will be compared with a standard single-frequency clinical immittance test battery routinely used in the assessment of auditory function in Veterans. Aim 1 seeks to evaluate the accuracy of the WB test battery in the differential diagnosis of middle-ear pathology and related conductive hearing loss by comparing the sensitivity and specificity of the WB battery to the traditional immittance battery for the following disorders common in Veterans: tympanic membrane perforation, serous otitis media, cholesteatoma, and otosclerosis. Aim 2 seeks to modify a WB ASR test to provide automatic detection of the ASR threshold for comparison with the traditional single-frequency ASR threshold. Aim 3 seeks to validate the use of TEOAE and SSOAE tests in Veterans to assess cochlear status, and evaluate their test performance in classifying ears with normal hearing and sensorineural hearing loss. Finally, Aim 4 seeks to compare the diagnostic accuracy of the full WB test battery with the full single-frequency admittance test battery to detect any type of hearing loss including sensorineural, conductive and mixed. The hypothesis is that the WB test battery is more accurate than the traditional immittance test battery in identifying ears with normal auditory status and ears with a range of risks for auditory pathology. Plan: This will be a multi-site research project with data collection at two VA sites: the Portland VA Medical Center, National Center for Rehabilitative Auditory Function (NCRAR) and the Mountain Home VA Medical Center. WB tests will be developed in collaboration with Dr. Douglas Keefe of the Boys Town National Research Hospital. Methods: Human subjects will be recruited for this study who have had a hearing evaluation from the VA Audiology Clinics at the Portland VAMC and Mountain Home, VAMC. These subjects will respond to flyers or be part of a human subject volunteer registry established at each site. Since the focus on the proposal is to evaluate the use of a WB test battery in comparison with the traditional battery in evaluating patients seen at VA Audiology clinics, the recruitment of subjects from clinic populations is critical. Across the 4 years of the study we will recruit a total 640 subjects, 320 from each site. This number of subjects will be required to obtain sufficient numbers of subjects with a variety of hearing disorders and pathologies to allow a comparison of results for traditional and wideband tests. All subjects will receive the same clinical and WB test battery. The clinical immittance tes battery will consist of 226 Hz tympanometry, and ASR threshold testing. The WB battery will consist of ambient pressure and tympanometric absorbance tests, an automated ASR threshold test, and finally a transient OAE test and a synchronous-spontaneous OAE test that will be developed in the first year of the study. Data will be analyzed to compare the utility of the WB and single-frequency tests in the differential diagnosis of conductive, mixed, and sensorineural hearing loss in Veterans. Any improvements found in the diagnostic performance of the WB test battery compared to current clinical procedures would provide an integrated set of auditory tests to more effectively and efficiently evaluate auditory function in Veterans.